[woodsyi]

Hey woodsyi,

With the Hemps, I think you are going to find that the 1.5uF cap selection will cross over way too low. Mine is much like Buddy's, he is using a .47, mine is like a .22 (my Lowthers are a little more extended than Buddy's Fostex). If I were you, I'd order a .47 and then a few .1uF metalized poly IC's (Illinois Capacitors) from Digikey. They are cheap and will do just fine for dialing in your XO point. After you find where it sounds best, then buy a decent cap. I think you will find yourself settling between a .2 and a .4uF on the Hemps.

Also, that Fostex L-Pad is the identical one sold at Parts Express for a few bucks less (if that matters). Speaking of PE, they have some cheap caps too. You may look at the Janzen Cross Caps. You can easily get by with a 50V cap. Don't worry about soldering while you are dialing the XO in as you'll be adding and subtracting caps on the fly. You may want to pick up a .047uF cap just to do that last little tweak on the XO point.

Oh, don't forget you'll need to reverse the phase on the tweeter when you connect it. Just place the cap on the positive terminal and then flip positive and negative when you connect it to the binding posts. It's pretty simple.

Thanks for the pointers Scott and everyone.  My thinking was the 8" hemp could use the assistance from the super tweeters from lower frequency but I will order some small caps and play around.  It's a learning experience for me on this path.  I really like the voices on this little combo but it does suffer in the highs in comparison to my main rig.  I want to see if the super tweeter will make an improvement in this area to my ears.

thanks, dave, for educating me about the passive x-over for supertweeters.   Smile  but, i am curious about your comments on the marchand x-over - i have never heard any amplifier degradation that has had a marchand x-over placed in front of it....

Doug,

After I heard the improvement going from xm44 to xm126, I can't say that xm9 or xm44 (or any other active crossover) does not get in the way in some way.  In multi-way speakers, I think the inherent advantage of active xover with dedicated amp per driver more than makes up for the veiling aspect of additional circuitry.  I am reluctant to impose anything on a crossoverless single driver speaker.  I think a passive highpass on the super tweet with nothing on the mains (just the natural roll off) is the way to go.  I guess the trick is to get the right point since the roll off is also supposed to be 6dB/octave slope.  Once I  get it right, I will order the frequency module from Phil and I will try the active x-over as an experiment.  I think I will know what i will hear but you never know.  Isn't this a fun hobby?

[konut]

You might want to consider the XM46 passive line level Xover. As its not active, it does present a 1db insertion loss in the circuit. This shouldn't be a problem particularly if you are using a preamp. I use XM46s for high pass duties on my Omega A8s to integrate a subwoofer, at 70hz, 24db per octave, with a passive preamp and still have plenty of gain for beyond sane levels. If you went this route, you would need an extra amp, stereo, and 4 XM46s. 2 for high pass, 2 for low pass. You can choose the slope and frequency, as Marchand will have the components custom wound to your requirements. Opinion alert! My XM46s are as transparent a component as I have ever used. YMMV.

Edit;
I've been meaning to post to this topic but have been busy of late. A discussion about using a super tweeter with just a cap to integrate between myself and Danny Richey can be found here  http://www.audiocircle.com/index.php?topic=31585.msg281684;topicseen#msg281684  I believe that Danny makes some excellent points pertinent to this thread.

[planet10]

am curious about your comments on the marchand x-over - i have never heard any amplifier degradation that has had a marchand x-over placed in front of it....

I used the XM9 for years with Acoustats + a pair of woofers. NAIM 160s (1 per acoustat) + various woofer amps. When i moved to more efficient speakers (with some bass on their own), i decided i'd rather live without the veil from the XM9 and sold it (an obsuring of information, and reduction in downward dynamic range).

The passive XM has always intriguied me, but i haven't heard it.

dave

[doug s.]

hi rim,

yes, i agree w/you - to some extent, a crossover will get in the way.  but, imo, a quality s/s x-over, (like marchand), is so transparent, that i don't think anyone would be able to hear the difference when in the signal path.  your tubed xm126, on the other hand...  i bet you like it better because it's technically less transparent than the s/s marchands!  you yust like the tube distortion!!!     don't get me wrong, i like it too, i think tubes rule!!!   

yes, i'm certainly anxious to hear the results of your experiments.  i may be wrong, but it seems all the added circuitry of a marchand, if on the active side, before the amps, will be more transparent than adding a cap & running the supertweeter in parallel. 

my deqx pdc2.6 showed up at work on monday, and as it was raining this morning, i didn't take my buell to work, so i will take this puppy home & start the learning curve...  and, see wazzup w/these full-range fostex fe-103's i have...    aa

and, yes, this hobby is all right.  listening to music ain't half-bad, either!   

doug s.

Doug,

After I heard the improvement going from xm44 to xm126, I can't say that xm9 or xm44 (or any other active crossover) does not get in the way in some way.  In multi-way speakers, I think the inherent advantage of active xover with dedicated amp per driver more than makes up for the veiling aspect of additional circuitry.  I am reluctant to impose anything on a crossoverless single driver speaker.  I think a passive highpass on the super tweet with nothing on the mains (just the natural roll off) is the way to go.  I guess the trick is to get the right point since the roll off is also supposed to be 6dB/octave slope.  Once I  get it right, I will order the frequency module from Phil and I will try the active x-over as an experiment.  I think I will know what i will hear but you never know.  Isn't this a fun hobby?

[doug s.]

so, the acoustats, sounded more open & dynamic than when run full-range, w/o the xm9?  this is interesting; also the 1st time i have heard this.  my experience 9& that of most others i have heard from), has been that whatever negative effects the marchand may introduce, the overall dynamics & transparency has been increased, due to the main speaker's not having to see that last octave or so.

the first time i used a marchand was to cross subs over to a pair of thiel 3.5's, which are quite detailed, even by today's standards.  every aspect of the thiel's performance was improved by crossing them over to subs at ~70hz w/the marchand.  except the high treble detail, which remained the same.

doug s.

am curious about your comments on the marchand x-over - i have never heard any amplifier degradation that has had a marchand x-over placed in front of it....

I used the XM9 for years with Acoustats + a pair of woofers. NAIM 160s (1 per acoustat) + various woofer amps. When i moved to more efficient speakers (with some bass on their own), i decided i'd rather live without the veil from the XM9 and sold it (an obsuring of information, and reduction in downward dynamic range).

The passive XM has always intriguied me, but i haven't heard it.

dave

[doug s.]

hey, planet 10 - a bit off topic, here, but how much would it cost me for two pairs of phase plugs for my fostex fe-103's, & for whatever other tweaks you may have for these drivers?     feel free to send me a private pm...

thanks,

doug s.

[woodsyi]

Yes,

Fostex T90A with just a .47uF cap without any attenuation to the Superhemps is adding a very nice twinkle in the highs that makes it more enjoyable.